Legal considerations play a key role in humanitarian assistance. Humanitarians may look to law to answer questions such as “what is permissible aid”, “who is an authorized humanitarian”, “what determines access to an affected context”, and “who can claim humanitarian protections and immunities”. But what are the specific areas of law with bearing on humanitarians in their everyday work? Is public international law—as traditionally advanced—the most appropriate field for this inquiry? This chapter argues for a reconstruction of the laws of humanitarian assistance from the perspective of humanitarian practitioners. From this viewpoint, it shows how prominent areas of public international law—such as international humanitarian law (IHL)—become relativized, and multiple other strands of law—public and private, international and domestic, hard and soft—are brought to the fore. Taking such a perspective helps to better understand the everyday practices of humanitarian assistance, including the strategic priorities of humanitarian actors, and the legal obstacles they face.